The invention relates generally to photovoltaic devices, and more particularly, to an imaging system for detecting defects in photovoltaic cells, modules, and method thereof.
Solar energy is considered as an alternate source of energy relative to other forms of energy. Solar energy conversion systems are used to convert solar energy into electrical energy. The solar energy conversion system typically includes photovoltaic modules, photoelectric cells, or solar cells that convert solar energy into electrical energy for immediate use or for storage and subsequent use. Conversion of solar energy into electrical energy includes reception of light, such as sunlight, at a solar cell, absorption of sunlight into the solar cell, generation and separation of positive and negative charges creating a voltage in the solar cell, and collection and transfer of electrical charges through a terminal coupled to the solar cell.
In solar module manufacturing line, it is helpful to identify local defects, hot spots, or the like in the solar devices, for example, thin-film photovoltaic modules to predict whether the solar module is prone to degradation or whether the solar module would fail. The conventional diagnostic method used for a solar module involves exposing a finished solar module under a light source that is calibrated to sun intensity, and then measuring current as a function of the applied voltage. This conventional technique provides information related to the power conversion efficiency of the solar modules but does not provide any information about the reliability of the solar module. Moreover, substantial power is consumed for the operation of the light source.
It is desirable to have a more effective system and method to identify defects in the photovoltaic devices, for example in thin-film photovoltaic modules.